Narrative:

Our aircraft was level 7000 ft at 210 KTS for an expected approach to runway 22L. Approach told us to descend with a good rate as we were #1 for runway 22L. During this descent, we encountered 2 TA's. The first we shallowed our rate and it passed, followed quickly by the second TA which almost immediately became a climb RA. We responded immediately with autoplt and autothrottles off and climbing within the indicated parameters. We were in clouds and the threat aircraft was on another frequency. We reported the RA and soon realized the closure was continuing. The lights off, the threat aircraft came through the clouds and we finally saw him climbing, maneuvering and almost co-altitude. Our best move now was to turn quickly and descend behind him. He passed in front of us within what seemed to be 1/4 - 1/2 mi. The visual action we took while in and out of clouds took us 1 min to stabilize and we found our speed at 290 KTS while below 10000 ft. We leveled and slowed at 5000 ft and approach changed our runway to runway 22R and we landed.

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Original NASA ASRS Text

Title: B737 FLC INITIATED TCASII EVASIVE MANEUVER FROM ANOTHER CONFLICTING ACFT IN IFR CONDITIONS UNDER C90 CTL.

Narrative: OUR ACFT WAS LEVEL 7000 FT AT 210 KTS FOR AN EXPECTED APCH TO RWY 22L. APCH TOLD US TO DSND WITH A GOOD RATE AS WE WERE #1 FOR RWY 22L. DURING THIS DSCNT, WE ENCOUNTERED 2 TA'S. THE FIRST WE SHALLOWED OUR RATE AND IT PASSED, FOLLOWED QUICKLY BY THE SECOND TA WHICH ALMOST IMMEDIATELY BECAME A CLB RA. WE RESPONDED IMMEDIATELY WITH AUTOPLT AND AUTOTHROTTLES OFF AND CLBING WITHIN THE INDICATED PARAMETERS. WE WERE IN CLOUDS AND THE THREAT ACFT WAS ON ANOTHER FREQ. WE RPTED THE RA AND SOON REALIZED THE CLOSURE WAS CONTINUING. THE LIGHTS OFF, THE THREAT ACFT CAME THROUGH THE CLOUDS AND WE FINALLY SAW HIM CLBING, MANEUVERING AND ALMOST CO-ALT. OUR BEST MOVE NOW WAS TO TURN QUICKLY AND DSND BEHIND HIM. HE PASSED IN FRONT OF US WITHIN WHAT SEEMED TO BE 1/4 - 1/2 MI. THE VISUAL ACTION WE TOOK WHILE IN AND OUT OF CLOUDS TOOK US 1 MIN TO STABILIZE AND WE FOUND OUR SPD AT 290 KTS WHILE BELOW 10000 FT. WE LEVELED AND SLOWED AT 5000 FT AND APCH CHANGED OUR RWY TO RWY 22R AND WE LANDED.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.